Geologic And Geochemical Characterization Of Cross-Communication Potential Within The Northern Edwards Aquifer System, Texas, Ingrid J. Eckhoff

Electronic Theses and Dissertations

The Edwards Aquifer is a large, complex groundwater system located throughout Central Texas in association with the Balcones Fault Zone. The San Antonio and Barton Spring segments of the Edwards Aquifer have been extensively studied in the past because they provide groundwater resources to the largely urbanized areas of San Antonio and Austin, respectively, and smaller communities along the Interstate 35 corridor. Previous research has been conducted on these southern and central portions of the Edwards Aquifer system, which have characterized the structural, hydrogeological and geochemical variations within the highly karsted region. However, the Northern Segment of the Edwards Aquifer …

Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla

Electronic Theses and Dissertations

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression …

Speleogenesis And Delineation Of Megaporosity And Karst Geohazards Through Geologic Cave Mapping And Lidar Analyses Associated With Infrastructure In Culberson County, Texas, Jon T. Ehrhart

Electronic Theses and Dissertations

The Gypsum Plain region of the Delaware Basin hosts approximately 1800 km² of the Castile Formation outcrop. A myriad of karstic developments from closed sinkholes to large multi-kilometer cave systems have been documented within the region. Karst studies on the distribution and speleogenetic evolution within Castile strata began within the last decade with ever increasing data resolution. In this study, a combination of both physical field surveys and analyses of high resolution (~30 cm accuracy) LiDAR data was used to create a theoretical model for karst development across the region. This idealized model considers speleogenetic formation type variations (hypogene …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Cone In Cone Concretions Of The Stanley Group In Southeastern Oklahoma, Kyle B. Ayres

Electronic Theses and Dissertations

Cone in cone concretions found in the Stanley Group of Southeastern Oklahoma have a variety of external and internal attributes which allow diagenetic and theoretical models of formation to be hypothesized. Stanley Group carbonate cone in cone concretions are initially formed in sulfur reducing horizons at shallow burial depths in a poorly circulated possibly deep trough containing siliceous sediments and organic matter. Collected concretions near the town of Smithville, Oklahoma displayed four different external morphologies and four variations of mineral constituents. All concretions contained microscopic cones which initiated diffusion and/or fluid patterns and is an early cementation process that directly …

Characterization Of Lower Permian Carbonate Subaqueous Gravity Flows In Crockett County, Texas, Wesley L. Turner

Electronic Theses and Dissertations

Transitional sediments on carbonate ramp slopes act as a link to relatively well-studied platform and basin depositional environments. In the southern Midland Basin, the key to understanding the relationship between these environments lies in the allochthonous gravity flow sediments found on the slope. Here, a succession of various gravity flow deposits is used to interpret how base level fluctuations affect the type of deposits found on the slope and their effect on the deep basinal environment. This study utilizes core samples from the Wolfcamp Formation adjacent to the Central Basin Platform in five wells in Northwest Crockett County, Texas. The …

An Investigation Of Hydrogeologic, Stratigraphic, And Structural Controls On Acer Grandidentatum Communities In A Karst Landscape, Owl Mountain Province, Fort Hood Military Installation, Texas, Melinda S. Faulkner

Electronic Theses and Dissertations

The Owl Mountain Province is located within the Fort Hood Military Installation, an approximately 880 km2 installation established in the 1940s in Bell and Coryell counties, Texas, which has undergone extensive land use changes associated with military training, maintaining much of the vegetation in early succession. This study investigates thelithologic, stratigraphic, and structural controls on the hydrologic, hydrogeologic, and geomorphologic evolution of the Owl Mountain Province as expressed by mesic vegetation communities, including Pleistocene relicts Acer grandidentatum, within karst terrains. These systems exhibit complexly overprinted speleogenetic evolutions within a dynamic groundwater regime resulting from regional climate shifts throughout the …

Speleogenesis Of Critchfield Bat Caves And Associated Hydrogeology Of The Northern Edwards Aquifer, Williamson County, Texas, Ashley N. Landers

Electronic Theses and Dissertations

Karst development in the Edwards Aquifer has been significantly studied in the San Antonio and Barton Spring Segments; however, karst development remains poorly studied in the Northern Segment. Detailed characterization of the Northern Segment is vital for future water conservation because of increasing urban sprawl along the Interstate 35 corridor. The Northern Segment of the Edwards Aquifer consists of Lower Cretaceous strata of the Comanche Peak, Edwards, and Georgetown formations. The stratigraphy is dominated by Edwards Limestone as it is the only formation that crops out in the study area.

Karst, stratigraphic, GIS, and geochemical studies were conducted to evaluate …

The Stratigraphic Position Of Fossil Vertebrates From The Pojoaque Member Of The Tesuque Formation (Middle Miocene, Late Barstovian) Near Española, New Mexico, Garrett R. Williamson

Electronic Theses and Dissertations

The stratigraphy of the Pojoaque Member of the Tesuque Formation near Española, NM is not well understood. This region, during the Middle Miocene, represented a dynamic alluvial fan-fluvial-lacustrine environment within the Española Basin while the Rio Grande Rift was active. Cavazza (1986) identified two paleodrainage systems (lithosome A, basin-margin facies and B, basin-floor facies) by means of sandstone and conglomerate petrology, paleocurrent, and sedimentary facies analyses. After x-ray diffraction analyses of claystones within lithosome B, mordenite was discovered, which is a zeolite mineral commonly found within volcanic rocks. This is significant because the presence of mordenite confirms Cavazza’s (1986) conclusion …

Evaluation Of Groundwater Quality In Paleozoic Aquifers Using Gis Techniques, Central Texas, Garrett R. Harris

Electronic Theses and Dissertations

Lab analyses of groundwater chemistry from monitoring wells completed in the Paleozoic Aquifers surrounding the Llano Uplift of Central Texas has been recorded and made available to the public through the Texas Water Development Board (TWDB). This study evaluated the results of these data dating back to the 1940s to determine changes over time, the dynamics of the hydrologic system, and the locations where hydraulic connectivity is most probable. The initial results established two distinct hydrologic systems that required the separation of the northern from the southern region. The northern sub-region (NSR) contains the largest expanse of continuity of both …

Geology Of The Northern Llano Uplift, Junction To Llano, Texas, R. Larell Nielson, Chris Barker

Faculty Publications

This year's Texas Academy of Science Geology Field Trip will visit nine interesting locations in two different areas in the Texas Hill Country (Figure 1). In the first area we will look at the Cretaceous stratigraphy around Junction, Texas (Figures 1, 2, 3, and 4). The expedition will then travel to the northern part of the Llano uplift and study Cambrian and Precambrian stratigraphy and structure of the northern Llano Uplift (Figures 4 and 5). Stop 9 will be at Cooper’s BBQ for lunch.